Electronic Expansion Valve Pi Control; Step Control Of Outdoor Unit Fans - Daikin VRV III REYQ8PY1B Service Manual

Basic Control
2.3

Electronic Expansion Valve PI Control

Main electronic expansion valve EVM control
When the outdoor unit heat exchanging is performed via the evaporator (20SA is set to ON),
this function is used to exert PI control on the electronic expansion valve (Y1E or Y3E) so that
the evaporator outlet superheated degree (SH) will become constant.
SH = Tg - Te
Subcooling electronic expansion valve EVT control
In order to make the maximum use of the subcool heat exchanger, this function is used to exert
PI control on the electronic expansion valve (Y2E, Y5E or Y3E) so that the evaporator-side gas
pipe superheated degree (SH) will become constant.
SH = Tsh - Te
Refrigerant charge electronic expansion valve EVJ control
While in automatic refrigerant charge mode, this function is used to exert PI control on the
opening degree of the electronic expansion valve (Y2E or Y4E) in response to outdoor
temperature and close the valve after the completion of refrigerant charge.
For normal operation, fully open this electronic expansion valve.
2.4

Step Control of Outdoor Unit Fans

Used to control the revolutions of outdoor unit fans in the steps listed in table below, according to condition changes.
STEP No.
8HP 10HP
0 0
1 285/255 285/255
2 315/285 315/285
3 360/330 360/330
4 430/400 430/400
5 590/560 590/560
6 690/660 690/660
7 820/790 820/790
8 920/890 920/890
9 920/890 920/890
Fan1/Fan2 Fan1/Fan2 Fan1/Fan2 Fan1/Fan2 Fan1/Fan2
* Figures listed above are all those controlled while in standard mode, which vary when the system is set to high static
pressure or capacity precedence mode.
114
Single type
12HP 14HP
0 0 0
285/255 285/255
315/285 360/315
360/330 395/365
430/400 480/440
590/560 560/530
690/660 760/730
820/790 960/930
951/931 1125/1095 1155/1125
1020/990 1125/1095 1200/1170
SH: Evaporator outlet superheated degree
(°C)
Tg : Suction pipe temperature (°C) detected
by the heat exchanger gas pipe
thermistor R2T.
Te : Low pressure equivalent saturated
temperature (°C)
SH: Evaporator outlet superheated degree
(°C)
Tsh:Suction pipe temperature (°C) detected
by the subcool heat exchanger outlet
thermistor R5T
Te: Low pressure equivalent saturated
temperature (°C)
Fan revolutions (rpm)
16HP M8 M10
0 0
285/255 350 350
360/315 370 370
395/365 400 400
480/440 450 450
560/530 540 560
760/730 610 680
960/930 680 710
710 750
796 821
Multiple type
M12 M14
0 0 0/0
350 230/0
370 380/0
400 290/260
450 375/345
560 570/540
680 720/690
710 910/880
775 1091/1061 1091/1061
870 1136/1106 1136/1106
Fan1/Fan2 Fan1/Fan2
SiBE37-701
M16
0/0
230/0
380/0
290/260
375/345
570/540
720/690
910/880
Function